Tube containers can be decorated in various ways depending on the structure of the tube container and how it is made. By decoration is meant all of the indicia that is placed on the tube. This includes brand names, designs and general information printing. Tube containers can be decorated before or after being fully formed. Laminate tubes can be decorated before the tube is fully formed. The webstock from which the body of a laminate tube is formed will be printed when in sheet form with this printed webstock then being formed into the tube body. This webstock can be printed on the exterior surface, or on an inner layer of the laminate. An inner layer such as a paper or film layer can be printed with the decoration. If the tube body is made by extrusion molding or by blow molding, it usually will be decorated after the tube body or tube has been made and prior to filling and sealing. In this latter instance, each tube is put onto a mandrel with the tube surface being printed by relative motion between the tube and a print surface. In such tubes the tube decoration is on the exterior surface. Any one of these techniques can be used to decorate conventional tube containers, such as those used for dentifrices, lotions, shampoos, ointments, hair dressing, foods and other products packaged in tubes.
A new type of decoration for a tube container is holographic decoration. Such a decoration cannot be printed onto the exterior surface of a formed tube. A tube construction technique that can be used for creating holographic effects is a laminate tube. However in use with laminate films there is a tendency for the holographic films to delaminate. One reason is that the traditional holographic films are metallized films. Such metallized holographic films, their structure and their manufacture are described in U.S. Pat. No. 5,200,253. However since in most laminate tubes there will be an overlap longitudinal seal, one edge of the laminate will potentially be exposed to the contents of the tube. This presents the problem of the tube contents reacting with the metal in the holographic film with a delamination of the film. Such a delamination in the area of the longitudinal seal will cause the longitudinal seal to weaken and in many instances to fail.
This problem is solved in the present tube containers since the holographic film will be a non-metallized holographic film. It usually will be a polyester film. Also since polyester films have low moisture barrier properties they will have to be used in the form of a laminate with another film providing the needed moisture barrier properties. Further since the holographic film will be a polyester film it has been found that it cannot be the outermost layer or innermost layer of the tube laminate structure. This is the case since in the construction of a laminate tube the innermost layer must be a layer that can be heat bonded or compression molded to the upper shoulder part of the tube, and heat bonded to the outer laminate layer in forming the longitudinal overlap seal to form the tube body. In the heat bonding of the shoulder to the tube body, the shoulder is made separately from the tube body and bonded by heat to the shoulder. The inner layer of the tube body is bonded to the shoulder. In compression molding of the shoulder to the tube body, the shoulder is formed onto the tube body. That is, it is simultaneously formed and bonded to the inner film layer of the tube body. The longitudinal overlap seal is produced by heat and pressure on the two overlapped edges of the laminate (edge of inner layer and edge of outer layer) to form the sheet webstock into the tube body.
Whether the shoulder is attached to the tube body by heat bonding or compression molding, and forming the longitudinal overlap seal by heat bonding, the innermost layer of the tube body must be of a plastic bondable to the tube shoulder, and to the outermost layer of the tube body. Since like plastics bond best to like plastics, the innermost layer of the webstock preferably should be the same as the shoulder and as the outermost layer of the tube body. Since the shoulders are usually made of a polyene polymer such as polyethylene, polypropylene, polybutene, polybutadiene or an ethylene-propylene copolymer, the innermost layer should likewise be a polyene, and preferably the same polyene. Consequently the preferred structure for the present laminate is a polyene layer bonded to each side of the polyester holographic film. Polyenes provide a good moisture barrier and bond well to the same or other polyenes. Such a structure will provide for a good bond to the shoulder, a strong longitudinal seal and a durable crimp seal at the bottom of the tube.